Yes but Oleander leaves are apparently extremely bitter, and I presume unripe ackee probably also has some kind of undesirable taste to it.

Basically I propose that everything that is tasty to us in its natural state, and doesn't immediately disgust us (like chili, garlic, noni, unripe fruits in general and many leaves) are healthy for us.

This is the idea, but I'm open for exceptions of course, but have yet to have heard about any. Most unhealthy/toxic foods have a disagreeable odor and/or taste in the mouth.

Most foods contain toxins I guess, but to the degree that the body can tolerate them, the sense of taste will allow it.